Network load refers to the amount of data that is transferred or received over a network. Since Linux distributions are very often used as servers, the network load on the server becomes a major issue for Linux system or server administrators.
Basically, it is about how the bandwidth is used in the network; how many packets are being sent/received, and so on. Today, let us find out how we can check the network load on a Linux server.
previous requirements
The commands explained in the article can also be tested on a desktop Linux machine. However, you can try them with a Linux server to really get a handle on it. You can try to install servers Apache o Nginx and host a sample website on them.
Check Linux network load using Netstat and SS commands
Netstat is a popular command for everything related to network analysis. It is not available on Linux distributions by default. Although the development of netstat it is now stopped, it is replaced by the command ss which is available by default in Ubuntu , CentOS etc.
To install netstat run the following on Debian and their derived distributions:
$ sudo apt install net-tools
In RedHat and its derived distributions, run:
$ yum install net-tools
For an overview of the network load, you can call both a netstat as a ss with the mark -s. netstat gives the output with more depth, while ss gives a summary of the load.
$ netstat -s
Check Linux network statistics
This is an abbreviated output shown in the following screenshot. The section TCP it will also display a summary of connections and packet transfers for UDP.
$ss -s
Check Linux network connections
Note that it shows the packets for each protocol ( TCP , UDP ), and at the top shows the summary of connections; established, closed, etc.
Check Linux Network Resource Usage With Sar Command
Another command that is very useful not only for network administration but also for general system administration is the sar command which is used to find any type of resource usage.
To install the sar command in Debian , Ubuntu or other derivatives, use:
$ sudo apt install sysstat
In RedHat , Fedora and other derivatives, run:
$ sudo yum install sysstat
Once you have installed the command, run the following to enable the command to capture statistics.
$ sudo service sysstat restart
The syntax for displaying network traffic with sar es:
$ sar -n Repeticiones de intervalo de protocolo
Here, -n means we are calling sar for network statistics and the ‘ Protocol ‘ can be IP, TCP, UDP, DEV (which shows the traffic for each network interface like Ethernet or Wifi), etc.
$ sar -n DEV 2 5
Check network interface traffic
Check the load of other protocols like TCP.
$ sar -n TCP 2 3
Check network TCP traffic
Conclusion
In this article, we describe three commands that can be used to monitor and verify network load on Linux. Be sure to review the command line man pages for these commands for more information on more options.
$ man netstat $ man ss $ man sar
Thank you for reading! Which tool do you prefer to use to check Linux network load? Let us know in the comments below!